JPH05305625A - Multi-cavity injection molding equipment of optical disc substrate - Google Patents

Abstract

PURPOSE:To contrive to simultaneously mold a plurality of optical disc substrates and enhance mass-productivity by a method wherein an injection molder is equipped with a mold, in which a plurality of cavities for simultaneously molding the optical disc substrates are formed, and a plurality of nozzles, through which molten resin is fed in the mold. CONSTITUTION:The injection molding equipment concerned is equipped with a mold 12, in which a plurality of cavities 11 for simultaneously molding a plurality of optical disc substrates, and an injection molder 13 having a resin feeding mechanism part 19 for feeding molten resin in the mold 12. The mold 12 is equipped with sprue bushings 15 having sprues 14 opening to the centers of respective cavities 11. Punches 16, each of which bores a center hole in each optical disc substrate molded in each cavity 11, are provided opposite to the sprue bushings 15. The injection molder 13 has plurality of nozzles 17 corresponding to the respective cavities 11, which communicate with a resin feeding mechanism part 19 through respective branch runners 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk substrate such as a compact disk having recorded information by concave and convex pits, a magneto-optical disk for reading recorded information utilizing optical characteristics, magneto-optical interaction and the like. It is related to injection molding equipment that takes multiple pieces.

[0002]

2. Description of the Related Art An optical disk substrate having an uneven pit which is usually made of a transparent resin or a smooth surface which does not depend on the uneven pit has its optical disk substrate at the center thereof as shown in FIG. The center hole 1 used for mounting on the rotation drive unit is formed by drilling, and the substrate surface around the center hole 1 is required to have uniform and uniform optical characteristics such as birefringence. Therefore, in molding this optical disk substrate, the injection opening by injection of resin into the cavity of the molding die is at the center of the optical disk substrate, that is, at the portion where the central hole of the disk substrate is formed. It is forced to be provided. That is, in the molding die for this optical disk substrate, it is necessary to provide a resin injection sprue for each molding cavity.

Usually, an injection molding apparatus for molding the optical disk substrates one by one is used for molding the optical disk substrates. However, molding the optical disk substrates one by one in this manner has a problem of low mass productivity.

Therefore, molding of this optical disk substrate
Attempts have been made to manufacture and use an injection molding machine capable of simultaneously molding two or more sheets.

The ones currently being attempted to be produced are
In general, it is composed of a mold having a plurality of cavities for molding an optical disk substrate, and an injection molding machine for melting and feeding resin into the mold, and a molten resin runner is provided on the mold side corresponding to each cavity. Alternatively, a plurality of similar runners connected to sprues provided for the respective cavities are provided.

However, in this type of injection molding apparatus, when the resin is not used for several hours, the resin melted by heating may be decomposed, so that so-called resin purging for taking out the resin is necessary. However, when the above-mentioned structure is adopted, handling problems such as difficulty in this resin purging occur.

[0007] As another attempt, a resin feeding section for feeding molten resin under pressure, that is, a screw mechanism, is provided on the injection molding machine side for feeding resin in correspondence with the sprue on the die side. There is something.

However, in this case, there is a disadvantage that the cost is increased because it is necessary to design and manufacture a special injection molding machine in which a plurality of screw mechanisms are provided.

[0009]

SUMMARY OF THE INVENTION The present invention has a simple structure, can easily perform handling and maintenance such as resin purging, and can mold a plurality of optical disk substrates at the same time, thus improving mass productivity. (EN) Provided is an injection molding apparatus for taking a plurality of optical disk substrates, which is capable of being processed.

[0010]

As shown in FIG. 1 which is a sectional view of the present invention, a mold 12 having a plurality of cavities 11 for simultaneously molding a plurality of optical disk substrates is formed. The mold 12 is provided with an injection molding machine 13 having a resin feeding mechanism portion 19 for feeding the molten resin.

The mold 12 has a sprue bush 1 having a sprue 14 opening at the center of each cavity 11.
3 is provided.

The injection molding machine 13 is provided with a plurality of nozzles 17 corresponding to the number of cavities 11 with respect to the resin feeding mechanism section 19, and the molten resin is pressurized and fed from the resin feeding mechanism section 19 to these nozzles 17, respectively. To do.

On the other hand, the sprue bush 1 on the die 12 side
The optical disc substrate molded in each cavity 11 by penetrating through the sprue bush 15 along the central axis of each cavity 11 from the side opposite to the arrangement side of 5 along with the central axis of each cavity 11 while pressing and retracting from each cavity 11. A punch 16 having a central hole is provided in the.

On the injection molding machine side, a fixed platen 21 having an arrangement hole for a locate ring 20 for holding the sprue bush 15 by pressing and retracting the punch 16 by restricting it to a minute movement is provided.

[0015]

As described above, in the structure of the present invention, a plurality of optical disk substrates are injection-molded by the mold 12 having the plurality of cavities 11, so that mass productivity is excellent.

Further, in the structure of the present invention, a nozzle 17 corresponding to each cavity 11 of the mold 12 is provided on the injection molding machine 13 side for supplying the resin, that is, a plurality of runners 18 are provided. Therefore, compared with the case where it is provided on the mold 12 side,
The structure and configuration are simplified, cost is reduced, and handling such as resin purging is easy.

Also on the injection molding machine 13 side, there is only one resin feeding mechanism 19 for the plurality of nozzles 17, and the delivery end, that is, the runner 18 is divided into a plurality of nozzles 17.
Since it is sufficient to lead to, it is possible to suppress the cost increase.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be further described with reference to FIG. The example of FIG. 1 shows a case where a vertical structure is adopted in which two optical disk substrates are taken.

The mold 12 includes plates 31 and 32, respectively.
Hold holes 41 and 4 are provided in through holes provided in and, respectively.
Two disk-shaped cavities 1 held by 2 and
The fixed-side mold 51 and the movable mold 52 that compose 1 are held. Reference numeral 23 is a separation surface of the mold, a so-called parting surface.

On the fixed side of the die 12, a sprue bush 15 having a sprue 14 centered on the central axis of each cavity 11 is disposed so as to penetrate therethrough, and the open end of the sprue 14 communicates with each cavity 11. Is done like this. The opposite side of the sprue bush 15 from the cavity 11, FIG.
In the upper end (in the following, upper and lower expressions are shown in FIG.
Flange 1 protruding to the outer periphery
5F is provided, and the concave portion 2 is provided on the fixed side of the mold 12.
The lower end of the sprue bush 15 is flush with the upper surface of the cavity 11 by abutting against the bottom surface of the cavity 4.

Further, each sprue bush 1 is attached to the die 12.
A locating ring 20 that abuts the upper surface of the flange 15F of the sprue bush 15 is attached by screwing or the like so that 5 can be moved slightly in the axial direction and that it can be prevented from coming off.

On the other hand, the fixed platen 2 on the injection molding machine 13 side
The fixed portion of the mold 12 is fixed to the first mold 1 by, for example, a mounting screw 62. In addition, the locate ring 20 is housed in the locate ring placement hole 21H formed in the fixed platen 21 via the insert 71 for the fixed platen.

Further, the injection molding machine 13 has a pair of resin feeding mechanism portions 19, and two branch runners 18 in which each nozzle 17 communicating with the opening at the upper end of the sprue 14 is formed. The Y-shaped resin supply passage 88 provided with is connected. Then, these nozzles 17 collide with the upper end of the sprue bush 15 of the mold 12 and press down the sprue bush 15 so that the opening of the sprue 14 is flush with the upper surface of the cavity 11. Resin feeding mechanism section 19
Is a screw, and is not shown
9 is supplied with resin pellets, which are melted by a heating means 90 such as an electric heater and agitated by rotation of the screw, and when the screw is pressed by hydraulic pressure, for example, resin such as polycarbonate or acrylic resin in a melted state. Is injected from each nozzle 17 and supplied into each cavity 11 through the sprue 14. Reference numerals 91 and 92 denote heating means for preventing the resin from solidifying, such as an electric heater provided on the outer periphery of the resin feed passage 88 and each runner 18.

On the other hand, the movable die 52 of the die 12 is provided with a punch 16 having the same diameter as the outer diameter of the sprue bush 15 coaxially with the sprue bush 15, and resin molding in the cavity 11. In the state where the above is performed, the upper end thereof is in the position where it forms the same surface as the lower surface of the cavity 11.

In this way, the resin is injected and injected into each cavity 11, and a disk-shaped optical disk is molded.

After this molding, the nozzle 17 of the injection molding machine 13
And, so to speak, the injection molding machine main body having the resin feeding mechanism 19 is retracted upward, and the sprue bush 15 can be slightly retracted upward, so that each punch 16 is pushed up and the optical disc substrate molded in the cavity 11 is centered. A hole is drilled. At this time, the sprue bush 15 is replaced by the punch 16
Since the flange 15F is slightly moved to the position regulated by the locate ring 20 and is retracted by the tip of the punch 15, the punch 16 extends over its entire thickness in the center of the optical disk substrate whose tip is molded. The center hole 1 shown in FIG. 2 is satisfactorily formed because it can be penetrated.

FIG. 1 shows a case where a vertical two-piece structure is used, for example, but a horizontal structure may be used, or three or more pieces may be formed, and various modifications may be made.

[0028]

As described above, according to the present invention, a plurality of optical disk substrates are molded, so that mass productivity is excellent.

Further, since the injection molding machine 13 is provided with the nozzles 17 for supplying the resin to the plurality of cavities 11, and these nozzles are provided so as to be branched from one set of the resin feeding mechanism section 19, a single piece is taken. This can be achieved simply by exchanging the nozzle portion depending on whether to use multiple nozzles or multiple nozzles. Further, the resin purging can be easily performed because it is not on the mold side.

Similarly, the fixed platen 21 is commonly used according to whether to take a single piece or a plurality of pieces, and only the insert 21H for the fixed platen arranged in the locate ring arrangement hole needs to be replaced. It has practically important and many advantages such as excellent compatibility with the structure of the parts and low cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of an injection molding apparatus for taking a plurality of optical disk substrates of the present invention.

FIG. 2 is a sectional view of an optical disk substrate.

[Explanation of symbols]

 11 Cavity 12 Mold 13 Injection Molding Machine 14 Sprue 15 Sprue Bushing 17 Nozzle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Hirayama 1561 Aikawa, Oigawa-cho, Shita-gun, Shizuoka CB Sony Corporation Shizuoka Factory

Claims (1)

[Claims] 1. A mold comprising a plurality of cavities for simultaneously molding a plurality of optical disk substrates, and an injection molding machine having a resin feeding mechanism for feeding a molten resin into the mold. The mold is provided with a sprue bush having a sprue opening at the center of each cavity, and the injection molding machine has a plurality of sprue bushes corresponding to the number of cavities with respect to the resin feeding mechanism. Nozzles are provided so that molten resin is pressurized and supplied to the nozzles from the resin feeding mechanism, respectively, and inside the cavities from the side of the mold side opposite to the side on which the sprue bush is arranged. The sprue bush is pushed through and retracted from each cavity along the center axis of each cavity, and is centered on the optical disk substrate molded in each cavity. And a platen having a locate ring arrangement hole for holding the sprue bush by pressing and retracting the sprue bush by restricting the movement to a small amount on the side of the injection molding machine. An injection molding machine that takes multiple optical disk substrates.